What's My Blood Glucose Level?

Just before lunch this afternoon I checked out the new FreeStyle Freedom Lite blood glucose monitoring system from Abbott Diabetes Care. The company’s public relations firm, Fleishman-Hillard, was nice enough to send me one of the first of these cute little meters and 10 test strips.

After carefully washing my hands, I quickly used one test strip for each of my 10 fingers. Within 20 minutes I had used them up. In that period I also used up my patience with this meter.

In that time I didn’t eat anything and didn’t exercise. But my blood glucose level apparently varied from a low of 77 mg/dl (4.3 mmol/L) to a high of 96 mg/dl (5.3 mmol/L. In fact, that difference of 19 points came between 1:35 p.m. and 1:37 p.m., just two minutes apart.

My Blood Glucose Level at 1:35 p.m. today** **** My Level Two Minutes Later**
I have no idea which of the 10 tests are right. The arithmetic mean (or average) was 87.6 mg/dl (4.9 mmol/L) and the middle value (or median) was somewhere between 88 mg/dl (4.9 mmol/L) and 91 mg/dl (5.1 mmol/L). I suppose that one of these numbers would be a pretty good guess. But do we really need to check our blood glucose 10 times to come up with an approximation?

We probably do. I also compared the results from the FreeStyle Freedom Lite with those from the AgaMatrix Jazz, which I praised for accuracy and precision here recently. The Jazz meter measured my blood glucose level consistently higher than Abbott’s new meter did. But even the Jazz wasn’t completely consistent.

Consistency – which we technically call precision – comes before accuracy, as I wrote in an article for Diabetes Health magazine in 2004. So why is this new meter not even consistent with itself?

Lots of people with diabetes believe that our blood glucose meters have to be correct within a 15 percent margin of error. Some people think the margin of error is 20 percent.

Guess what? The U.S. government agency that approves the sale of new meters has no accuracy and precision standards. None.

That agency is the U.S. Food and Drug Administration. The then director of the FDA’s Division of Clinical Laboratory Devices, Steve Gutman, M.D., told me years ago that accuracy is not something they consider when they approve the marketing of blood glucose meters. He added that he expects that we will have a standard for meter accuracy after the FDA accepts the proposed International Organization for Standardization (ISO) standard. That standard will allow a 20 percent error. I hear that we are still waiting to act.

The FDA approved the FreeStyle Freedom Lite meter last year. The agency stated, as it usually does when it approves the sale of a new meter, that it was satisfied that the new meter was “acceptable and comparable in terms of safety and effectiveness to the performance of the predicate device.” In non-technical language this means that the FreeStyle Freedom Lite is as good as a meter that the FDA has already said could be sold in the United States, in this case an earlier Abbott Diabetes Care meter, the FreeStyle Freedom.

In fact, the FDA review shows that the Freedom Lite is better than the Freedom in three respects:

The biggie is that when you use a Freedom Lite meter you don’t have to manually code the meter to match a code number on the vial of test strips. Thus Abbott has joined the growing trend to codeless meters, following Bayer and Roche, which introduced meters that don’t require coding almost four years ago, as well as two smaller companies, Diagnostic Devices and AgaMatrix, more recently.

Now, only LifeScan among the major meter manufacturers lacks a no-code meter. Even its OneTouch UltraLink, one of which arrived via UPS today, still requires coding. This new meter works wirelessly with MiniMed Paradigm and Guardian devices.

A little improvement in the Freedom Lite over the Freedom is that the new meter will store up to 400 test results. That’s 150 more than the older meter.

3. The Freedom Lite will also compute a 7, 14, and 30 day average of your blood glucose readings. The older Freedom meter only knows how to figure out a 14-day average. These last two improvements are marginal at best.

However, the really big deal about the new Freedom Lite is something that FreeStyle meters always had, ever since Abbott bought the TheraSense company, which originally made them. These blood glucose meters still take the smallest blood sample size of any meter.

All FreeStyle meters take only 0.3 microliters of blood. No other meter takes less than 0.5 microliters. Several meters take ten times as much blood – 3.0 microliters – as FreeStyle meters do. The OneTouch Basic meter, which LifeScan no longer sells in the United States, required a huge a 10 microliter blood glucose sample.

If you decide to use a FreeStyle Lite meter at least you won’t be using up a lot of your blood. Unless you decide that, like me, you need to use 10 strips each time to check your level.